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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
181

A comparative study of Tosoh G11 and Bio-Rad D-100 analyzers for HbA1c analysis / En jämförande studie av Tosoh G11 och Bio-Rad D-100 för HbA1c -analys

Alvin, Maja, Lundin, Filippa January 2023 (has links)
Diabetes mellitus is one of the most common diseases worldwide. The continued prevalence increase, together with the complexity of the disease with severe long-term complications makes efficient diagnostical and monitorial methods very important. The determination of glycated hemoglobin, HbA1c, plays an important role in both, underlying the importance of high-quality analytical instruments. Whenever a new instrument is introduced into routine clinical use an evaluation is needed. This study evaluated the agreement between the new Tosoh G11 HbA1c high performance liquid chromatography system as a replacement for the Bio-Rad D-100 at the Chromatographic Department of the Institute of Laboratory Medicine, Faculty of Medicine, University of Debrecen. In total, 66 samples were analyzed using both analyzers and a Bland-Altman comparison was performed together with a correlation study. Additionally, a linearity check, optimal error and routine error testing was carried out specifically for the Tosoh G11. The results showed high agreement between measurements, r=0.9975 (p<0.001) for HbA1c mmol/mol and r=0.9971 (p<0.001) for HbA1c %. High repeatability and accuracy were observed of the Tosoh G11 with the highest variation coefficient of 1.50 % and linearity r =0.9999. The conducted study supports the replacement of the Bio-Rad D-100 to the Tosoh G11. / Diabetes mellitus är en av de vanligaste världsomfattande sjukdomarna. Fortsatt prevalensökning, tillsammans med den komplexa sjukdomsbilden innefattande allvarliga långsiktiga komplikationer gör effektiva diagnostiska och övervakande metoder väldigt viktiga. Bestämning av glykerat hemoglobin, HbA1c, spelar en viktig roll i båda, vilket kräver att analysinstrument av hög kvalitet finns. När ett nytt instrument introduceras inom kliniska rutinanalyser krävs utvärdering. Denna studie utvärderade överrensstämmelsen mellan det nya Tosoh G11 HbA1c högupplösande vätskekromatografisystemet som en ersättning för Bio-Rad D-100 på den kromatografiska enheten av laboratoriemedicin på Debrecens universitet. Totalt analyserades 66 prov med respektive instrument och Bland-Altman jämförelse genomfördes tillsammans med en korrelationsstudie. Dessutom utfördes ett linjäritetstest, optimal- och rutinfeltest specifikt för Tosoh G11. Resultaten visade en hög överrensstämmelse mellan mätningarna, r=9975 (p<0.001) för HbA1c mmol/mol och r =9971 (p<0.001) för HbA1c %. Tosoh G11 visade hög repeterbarhet och noggrannhet, med den högsta variationskoefficient på endast 1.50 % och en linjäritet på r=0.9999. Den genomförda studien stödjer Tosoh G11 som ersättning för Bio-Rad D-100.
182

Creating Software Libraries to Improve Medical Device Testing of the Pacing System Analyzer (PSA) at St. Jude Medical

Canlas, Joel 01 July 2011 (has links) (PDF)
Software testing, specifically in the medical device field, has become increasingly complex over the last decade. Technological enhancements to simulate clinical scenarios and advancements in communicating to medical devices have created the need for better testing strategies and methodologies. Typical medical device companies have depended on manual testing processes to fulfill Food and Drug Administration (FDA) submission requirements specifically Class III devices which are life supporting, life sustaining devices. At St. Jude Medical, software testing of Class III devices such as implantable cardioverter-defibrillators (ICDs), pacemakers, and pacing analyzers are given top priority to ensure the highest quality in each product. High emphasis is made on improving software testing for ease of use and for catching more software errors in each device. A significant stride in testing has automated the process and has provided software verification teams with the tools they need to successfully test and deliver high quality products. By creating software libraries which interact with communication to the other interfaces needed to test medical devices, test engineers can focus on fully testing device requirements and will not be concerned with how each test will interact with the device or any other testing tools. The main focus will be a specific St. Jude Medical device known as the Pacing System Analyzer (PSA). The PSA device will be used to demonstrate how verification engineers are able to benefit from software libraries and allow the testing process and test development to be fully automated. New technologies and standards will be created to simulate clinical scenarios and to communicate to new devices. The goal is to use software engineering principles to create standard test libraries which sustain these changes while still allowing testers to focus on finding issues for each device.
183

Разработка компактного дискретного фазовращателя ДМВ-диапазона : магистерская диссертация / Development of a compact discrete phase shifter for the UHF range

Овчинников, Е. Ю., Ovchinnikov, E. Y. January 2021 (has links)
Объектом исследования является дискретный фазовращатель ДМВ диапазона. Цель работы - разработка фазовращателя с требуемыми в техническом задании параметрами. В процессе работы был рассчитан и смоделирован фазовращатель в среде проектирования «АWR Design Environment», разработана электрическая принципиальная схема и перечень элементов, создан макет устройства и проведены его измерения. Моделирование ФВ проводилось с применением методов электромагнитного анализа и использованием в качестве основных активных элементов их S-параметров и Spice-моделей. В результате проведенной работы был создан макет фазовращателя с требуемыми параметрами. Результаты работы будут применены при создании фазированной антенной решетки метеорологического радиолокатора. / The object of the research is a discrete phase shifter of the UHF range. The purpose of the work is to develop a phase shifter with the parameters required in the technical specification. In the process of work, the phase shifter was calculated and modeled in the AWR Design Environment, an electrical schematic diagram and a list of elements were developed, a device model was created and its measurements were carried out. PV modeling was carried out using the methods of electromagnetic analysis and using their S-parameters and Spice-models as the main active elements. As a result of the work carried out, a prototype of a phase shifter with the required parameters was created. The results of the work will be used to create a phased array of a meteorological radar.
184

Counter-flow Ion Mobility Analysis: Design, Instrumentation, and Characterization

Agbonkonkon, Nosa 14 November 2007 (has links) (PDF)
The quest to achieve high resolution in ion mobility spectrometry (IMS) has continued to challenge scientist and engineers in the field of separation science. The low resolution presently attainable in IMS has continued to negatively impact its utility and acceptance. Until now, efforts to improve the resolution have mainly focused on better instrumentation and detection methods. However, since the resolution of IMS is diffusion limited, it makes sense to address this limitation in order to attain high resolution. This dissertation presents a new IMS technique, which utilizes a high electric field and opposing high gas flow velocity with the aim to improve resolution. This approach essentially reduces the residence time of ions in the analyzer. This new technique is called "counter-flow ion mobility analysis" (CIMA). Theoretical modeling of this new technique predicted that a resolution of over 1000 is possible, which is over one order of magnitude better than that of conventional IMS techniques currently used. A wind tunnel was designed and constructed to produce a plug gas flow profile that is needed for CIMA. The test region of the wind tunnel was used as the CIMA analyzer region and was constructed from power circuit boards, PCBs, (top and bottom walls) and conductive plastic side walls. An inclined electric field was created by applying suitable voltages to multiple electrode traces on the PCBs. This inclined field, when resolved into its x- and y-components, was used to oppose the counter-gas flow and transport the ions to the detector, respectively. The results obtained did not show an improvement over conventional IMS techniques because of a limitation in the voltage that could be applied to the analyzer region. However, the results predict that high resolution is possible if (1) the ratio of the electric fields in the horizontal (x direction) to the vertical (y direction) is within the range of 2--0.5, (2) very high electric field and high gas flow velocities are applied, and (3) wall effects in the counter-flow gas profile are eliminated. While the resolution obtained using the present instrumentation is far from what was predicted, the foundation for ultimately achieving high resolution has been laid. The use of a wind tunnel has made the instrumentation possible. As far as the author knows, this is the first time a wind tunnel has been used in chemical measurement instrumentation. Chapter 5 of this dissertation, reports a method developed for predicting the reduced mobility constants, of chemical compounds. This method uses a purely statistical regression analysis for a wide range of compounds which is different from similar methods that use a neural network. The calculated value for this method was 87.4% when calculated values were plotted against experimental K0 values, which was close to the value for the neural network method (i.e., 88.7%).
185

Cost-Effective, Focused Instrumentation for TT&C/COMMS Engineering

Williams, Steve 10 1900 (has links)
ITC/USA 2008 Conference Proceedings / The Forty-Fourth Annual International Telemetering Conference and Technical Exhibition / October 27-30, 2008 / Town and Country Resort & Convention Center, San Diego, California / The need for sophisticated tools in the expanding areas of Telemetry, Tracking and Control/Command (TT&C) and Communications (COMMS) system simulation, development, verification, analysis, maintenance, debug, and education is well understood. Emerging requirements for these toolsets include features, ease-of-use, performance, and price points that specifically address telemetry and signals work. And, while not yet as available, understood, or pervasively installed, these economical and focused tools are displacing high-cost, general-purpose Test and Measurement (T&M) equipment at an increasing rate.
186

Advanced Plasma Analyzer for Measurements in the Magnetosphere of Jupiter

Stude, Joan January 2016 (has links)
The Jupiter Icy Moons Explorer is a planetary exploration mission that aims to study the moons of Jupiter in the planet’s vast magnetosphere. Among the various instruments on board is the Particle Environment Package (PEP), that is led by the Swedish Institute of Space Physics (IRF) in Kiruna. The Jovian plasma Dynamics and Composition analyzer (JDC) is one of six sensors within PEP and focuses on the characterization of positive ions. To be able to measure their three-dimensional distribution and composition, in-situ and in high time resolution, JDC has to cover a large field of view of 2π sr, for the desired energy range, in just a couple of seconds. An electrostatic analyzer within the sensor determines the energy per charge of such particles and a time-of-flight mass spectrometer measures their mass per charge. Constraints on weight and the radiation environment of Jupiter drive the design of the sensor: small and lightweight to allow extra shielding, but still large enough to accomplish measurements in the harsh radiation environment of Jupiter. This work focuses on a new type of compact, electrostatic analyzer using spherical wedges and the start signal generation for the time-of-flight measurement using new venetian blind-type surfaces. Simulations on the electrostatic analyzer showed that the most promising design is a hybrid variant, using an inner shell with spherical wedges and a spheroidal outer shell. A prototype sensor was built and tested with successful results. A reflectron-type time-of-flight cell measures the time it takes for a particle to pass a linear electric field. The time measurement has to be very accurate and requires that all ions enter the reflectron from the same start position. Commonly this is achieved with thin carbon foils of some nanometer thickness to provide a very accurate start position. Upon impact and after leaving a foil, ions generate secondary electrons that act as start signals for the time measurement. Foils require a substantial pre-acceleration of several kilovolts for the ions to penetrate the foil, thus increasing the size and mass of the instrument. When incident ions are reflected at grazing angles from a surface, secondary electrons are released in the same way as with foils. To increase position accuracy during this reflection process, venetian blind-type start surfaces are investigated, where many smaller surfaces replace a large flat surface. The most promising sample was found to be micro pore optics, that were initially designed to focus gamma rays. In several experiments it could be shown that micro pore optics show good reflection properties when used as start surfaces in the time-of-flight measurement. Both improvements allow a more compact and lightweight sensor that can be better shielded against the harsh radiation environment in Jupiter’s system. Jupiter hosts the strongest radiation environment in the solar system, that could kill an unprotected human thousand times over. / JUICE, PEP
187

Development and implementation of a flow injection analyser with chemiluminescence for detection of sub-nanomolar Fe in seawater

Rentel, Raimund 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Iron is an essential micronutrient for all phytoplankton and is found in seawater at picomolar-level concentrations. For the first time in South Africa, a technique that utilizes a flow injection analyser (FIA) coupled with a chemiluminescence reaction has been developed for the analysis of Fe in seawater samples. The developed method is an improvement on similar available methods and uses commercially available resin (IDA) as opposed to the one that requires synthesis in the laboratory. Furthermore, the method requires reduced reagent concentrations thereby providing better results in a cost-efficient and easy manner. The improvements resulted in better precision while eliminating the loss of resin through bleeding, a common problem when using 8-HQ resin as per prior methods. Method validation was performed using internationally calibrated reference material provided by GEOTRACES and the values obtained were within the error limits of certified range. An inter-laboratory calibration was also conducted as part of the verification of the system. Surface samples from the SANAE 51 cruise were analysed for dFe and TdFe. Subsequently, the method was implemented on the SANAE 53 voyage on board the SA Agulhas II, to assess trace metal sampling protocol for any contamination issues, as well as for the analyses of collected samples. Current results suggest some contamination during collection stages, but this is still to be verified by complementary data on macronutrients and chlorophyll. The method was successfully developed and implemented in a land based clean laboratory, as well as on board a vessel. / AFRIKAANSE OPSOMMING: Yster is „n noodsaaklike mikrovoedsel vir fitoplankton en word in seewater in pikomolêre konsentrasies gevind. Hierdie lae konsentrasies en potensiële besoedeling gedurende monsteropname vanaf „n skip se platform maak akkurate Fe-analise moeilik. Vir die eerste keer in Suid-Afrika is „n tegniek ontwikkel wat gebruik maak van „n vloei- inspuitinganaliseerder (VIA), met „n geassosieerde chemiluminessensiereaksie, om die analise van Fe in seewatermonsters uit te voer. In teenstelling met soortgelyke bestaande metodes wat labratorium-gesintetiseerde hars vereis, is die nuut-ontwikkelde metode „n verbetering wat gebruik maak van „n kommersieel-beskikbare hars (IDA). Verder vereis die metode verminderde reagenskonsentrasies wat sodoende beter resultate lewer op 'n koste-effektiewe en eenvoudiger wyse. Die verbeteringe het gelei tot verhoogde akkuraatheid en uitskakeling van die verlies van hars deur dreinering – „n algemene probleem wat ondervind is met die gebruik van 8-HQ hars in vorige metodes. Geldigheidsbepaling van die metode is met internasionaal-gekalibreerde verwysingsmateriaal, verskaf deur GEOTRACES, uitgevoer. Die waardes wat verkry is, was binne die foutgrense van die gesertifiseerde skaal. „n Interlaboratorium-kalibrasie is ook uitgevoer as deel van die verifikasie van die stelsel. Daarna is die metode geïmplementeer gedurende die SANAE 53 reis op die SA Agulhas II, om die spoormetaal-monsternemingprotokol vir enige besoedelingskwessies te evalueer, asook vir die ontleding van versamelde monsters. Huidige resultate dui op „n mate van besoedeling tydens die versamelingstadiums, maar dit moet nog geverifieer word deur aanvullende data van die totale oplosbare Fe, makrovoedingstowwe en chlorofil.
188

Building software tools for combat modeling and analysis

Chen, Yuanxin 12 1900 (has links)
Approved for public release, distribution is unlimited / The focus of this thesis is to use and leverage the strengths of dynamic computer program analysis methodologies in software engineering testing and debugging such as program behavior modeling and event grammars to automate the building and analysis of combat simulations. An original high level language METALS (Meta-Language for Combat Simulations) and its associated parser and C++ code generator were designed to reduce the amount of time and developmental efforts needed to build sophisticated real world combat simulations. A C++ simulation of the Navy's current mine avoidance problem in littoral waters was generated using high level METALS description in the thesis as a demonstration. The software tools that were developed will allow users to focus their attention and efforts in the problem domain while sparing them to a considerable extent the rigors of detailed implementation. / Major, Republic of Singapore Navy
189

Measurement and control of greenhouse gas emissions from beef cattle feedlots

Aguilar Gallardo, Orlando Alexis January 1900 (has links)
Doctor of Philosophy / Department of Biological and Agricultural Engineering / Ronaldo Maghirang / Emission of greenhouse gases (GHGs), including nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2), from open beef cattle feedlots is becoming an environmental concern; however, scientific information on emissions and abatement measures for feedlots is limited. This research was conducted to quantify GHG emissions from feedlots and evaluate abatement measures for mitigating emissions. Specific objectives were to: (1) measure N2O emissions from the pens in a commercial cattle feedlot; (2) evaluate the effectiveness of surface amendments in mitigating GHG emissions from feedlot manure; (3) evaluate the effects of water application on GHG emissions from feedlot manure; and (4) compare the photo-acoustic infrared multi-gas analyzer (PIMA) and gas chromatograph (GC) in measuring concentrations of N2O and CO2 emitted from feedlot manure. Field measurements on a commercial beef cattle feedlot using static flux chambers combined with GC indicated that N2O emission fluxes varied significantly with pen surface condition. The moist/muddy surface had the largest median emission flux; the dry and compacted, dry and loose, and flooded surfaces had significantly lower median emission fluxes. Pen surface amendments (i.e., organic residues, biochar, and activated carbon) were applied on feedlot manure samples in glass containers and evaluated for their effectiveness in mitigating GHG emissions. Emission fluxes were measured with the PIMA. For dry manure, all amendments showed significant reduction in N2O and CO2 emission fluxes compared with the control (i.e., no amendment). For moist manure, biochar significantly reduced GHG emissions at days 10 and 15 after application; the other amendments had limited effects on GHG emissions. The effect of water application on GHG emissions from feedlot manure was evaluated. Manure samples (with and without water application) were placed in glass containers and analyzed for GHG emission using a PIMA. For the dry manure, GHG emissions were negligible. Application of water on the manure samples resulted in short-term peaks of GHG emissions a few minutes after water application. Comparison of the GC and PIMA showed that they were significantly correlated but differed in measured concentrations of N2O and CO2. The PIMA showed generally lower N2O concentrations and higher CO2 concentrations than the GC.
190

Carbon Dioxide and Hydrogen Sulfide Emission Factors Applicable to Wastewater Wet Wells

Mudragaddam, Madhuri 14 May 2010 (has links)
Transport of wastewater in sewer networks causes potential problems associated with gases which include ammonia, carbon dioxide, carbon monoxide, hydrogen sulfide and methane, in regard to odor nuisance, irritation, toxicity, and microbially induced corrosion. The extent of these problems depends on the emission rates of gases in the sewer atmosphere. To limit these kinds of problems an estimate of the gases emitted from the sewer network is to be known. In consideration to the above mentioned problems, a research has been taken up to estimate the two gases, namely, carbon dioxide and hydrogen sulfide from sewer wet wells. In this method, using Landtec GEM-2000 plus a multi-gas analyzer, the sample gases were collected from the wet well of pump stations for five days. Using the collected samples the emission rates of carbon dioxide and hydrogen sulfide are estimated.

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